Estimation of the Thermal State of a Large Reflector Taking Into Account the Rods Mutual Shading

摘要

Truss reflectors of various profiles, shapes and sizes are used as antenna systems that are intended for operation as a part of space vehicles and orbital stations. In order to provide specific radio-engineering tasks performance, reflectors should satisfy strict requirements in the context of maintaining the reflecting surface shape during operation, as close as possible to the desired one. Apart from deflections from the nominal shape caused by technological factors and stresses that appear in a structure due to mechanical loads influence, thermal deformations with an uneven temperature distribution, caused by the rods mutual shielding, also has a significant influence on distortion of the reflecting surface. A method to estimate thermal state of large transformable reflectors that accounts rods mutual shielding is proposed in the current study. The method is based on a probabilistic approach. This approach implies that determination of the extent in which the rods shadow each other and is conducted by taking into account the probability of this event. The basic mathematics, that allow to obtain a quantitive evaluation that is close to the real one, are provided in the current study. The results that are obtained for real structures by means of a computer program based on the proposed approach demonstrate that a "shadow" effect influence on the unevenness of temperature distribution is significant. And this could cause shape deformation of the reflecting surface.